Cluster tool process chamber having integrated high pressure and vacuum chambers

ABSTRACT

A cluster tool includes a transfer chamber connected to a plurality of vacuum chambers. An additional process chamber connected to the transfer chamber includes a high pressure chamber assembly seated on a housing. The high pressure chamber assembly, which is adjustable between an open position and a closed position, includes an upper chamber portion and a lower chamber portion. Hydraulic cylinders mounted on the upper chamber portion and having chamber rods that attach to the lower chamber portion are configured to move the lower chamber relative to the upper chamber portion between the two positions. When the two portions are brought together into the closed, the high pressure chamber assembly forms a high pressure chamber suitable for processing wafers with supercritical CO 2 . Once the high pressure chamber is formed, a region between lower chamber portion and a housing may be evacuated to form a vacuum chamber outside a portion of the high pressure chamber.

RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.10/954,098, filed Sep. 30, 2004, now U.S. Pat. No. ______. The entiredisclosure of the above-identified parent application is incorporatedherein by reference

FIELD OF THE INVENTION

The present invention relates to a process chamber for semiconductorfabrication. More particularly, it pertains to a process chamberincluding a high pressure chamber assembly that is adjustable between anopen position and a closed position. When in the closed position, a highpressure chamber is formed, as is a vacuum chamber. The process chambermay be connected to a cluster tool to which other vacuum chambers areconnected.

BACKGROUND OF THE INVENTION

Cluster tools are well-known in the prior art. FIG. 1 is a simplifieddiagram of a cluster tool 100, as disclosed in U.S. Pat. No. 6,321,134,whose contents are incorporated by references. The prior art clustertool 100 is configured in a circular or round annular configuration.More particularly, as seen in this figure, the cluster tool 100 takes ona hexagonal configuration with six facets. That is, transfer chamber102, including a robot 104, is placed in a center region, which issurrounded by a plurality of vacuum processing chambers, shown by atleast reference numerals 106A, 106B, 106C, 106D and 106E. It isunderstood that the transfer chamber 102 is provided with a vacuum pump,or the like, as are the process chambers.

Connected to the transfer chamber 102 is a load lock 116 that may beported to a clean room where the wafers are stored. As is known to thoseskilled in the art, robot 104 typically has a hinged arm terminating ina wafer handle 110 for holding a wafer 108. The wafer handle may bedisk-shaped, prong-shaped or take on some other shape. Robot 104 caninsert and remove a wafer 108 or wafers from any one of the chambers106A-106E, or into the load lock 116, according to a desiredapplication.

FIG. 2 shows another prior art cluster tool 200 which is arranged anin-line or linear configuration. That is, transfer chamber 202,including a robot 204, is placed in parallel alignment with a pluralityof vacuum process chambers, shown by reference numerals 206A, 206B,206C, 206D, 206E and 206F. It is again understood that the transferchamber 202 is provided with a vacuum pump, or the like, as are theprocess chambers. A load lock 216 is also provided. Robot 204 can insertand remove a wafer 208 or wafers, which rests on wafer handler 210, fromany one of the chambers 206A-206F, or into the load lock 116, accordingto a desired application.

The individual chambers in either prior art cluster tool 100 or 200 maybe provisioned with necessary chucks, tools, valves, connections, andthe like, to effect one or more processing steps, all under thedirection of one or more controllers, as known to those skilled in theart. It is further understood that a variety of pumps, gas cylinder, ionsources, and the like, may be housed within, and/or connected to thevarious chambers.

As also known to those skilled in the art, the prior art cluster tools100, 200 are typically coupled to a controller. Such a controllerincludes a variety of elements such as a microprocessor based unit, ahard disk memory storage unit, input/output elements such as a pointerdevice (e.g., mouse), a keyboard and/or touch screen, mouse, and otherelements. The controller also may also be associated with a display suchas a flat panel display, cathode ray tube (“CRT”), and the like. Thedisplay has a graphical user interface that includes a menu. The menu ormenus can correspond to a variety of process recipes that are stored onthe hard drive or other memory device. The process recipes can be in theform of a computer program or programs that use computer codes in theform of software. The computer codes carryout the functionalitydescribed herein as well as others. A network interface may also beprovided.

As disclosed in U.S. Pat. No. 6,763,840, whose contents are alsoincorporated by reference, supercritical CO₂ may be used to clean asubstrate in a pressure chamber of a cluster tool. For this, thesubstrate is first placed in a pressure chamber and the chamber is thenpressurized. Next, CO₂ is introduced into the pressure chamber, and thesubstrate is cleaned with the CO₂. The CO₂ is next removed from thepressure chamber, and the pressure chamber is depressurized. Finally,the substrate itself is removed from the chamber.

SUMMARY OF THE INVENTION

In one aspect, the present invention is directed to a cluster tool. Thecluster tool includes a transfer chamber and at least one processchamber connected to the transfer chamber. The at least one processchamber comprises a housing and a high pressure chamber assemblyconnected to the housing. The high pressure chamber assembly comprisesan upper chamber portion, a lower chamber portion movable relative tothe upper chamber portion, and a plurality of hydraulic cylindersconnecting the two. The upper chamber portion and the housing define acompartment in which the lower chamber portion resides, the highpressure chamber assembly being adjustable between an open position inwhich the lower chamber portion is spaced apart from the upper chamberportion, and a closed position in which the lower chamber portioncontacts the upper chamber portion to thereby form a high pressurechamber enclosing a first space, a second space being defined within thecompartment between the lower chamber portion and a bottom wall of thehousing. A first valve is provided between the transfer chamber and thehousing.

Preferably, the cluster tool is adjustable between (1) a first state inwhich the first valve is open, the high pressure chamber assembly isopen and the transfer chamber and the compartment have a commonpressure; (2) a second state in which the first valve is closed, thehigh pressure chamber assembly is open, the transfer chamber has a firstpressure and the second space has a second pressure that is differentfrom the first pressure; and (3) a third state in which the first valveis closed, the high pressure chamber assembly is closed, the transferchamber has a first pressure, the second space has a second pressure,and the first space has a third pressure, the first and second pressuresbeing below atmospheric pressure and the third pressure being aboveatmospheric pressure.

In another aspect, the present invention is directed to a high pressurechamber assembly. The high pressure chamber assembly comprises an upperchamber portion, a lower chamber portion movable relative to the upperchamber portion, and a plurality of hydraulic cylinders connecting theupper chamber portion to the lower chamber portion. Tower chamberportion comprises a lower wall, and a lower plate having a front surfaceand a back surface, the lower plate's back surface abutting the lowerwall, the lower plate being provided with at least one through passagefor the conveyance of fluids, the back surface of the lower plate beingprovided with at least one laterally extending channel, for furtherconveyance of fluids. The high pressure chamber assembly is adjustablebetween an open position in which the lower chamber portion is spacedapart from the upper chamber portion, and a closed position in which thelower chamber portion contacts the upper chamber portion to thereby forma high pressure chamber enclosing a first space. The entry and exit offluids into this high pressure chamber is only through the upper chamberportion.

In yet another aspect, the present invention is directed to a method ofcleaning a wafer in a process chamber that is connected via a valve to atransfer chamber of a cluster tool, the process chamber including a highpressure chamber adjustable between an open position in which a wafermay be inserted or removed and a closed position in which said wafer canbe processed. The method comprises introducing the wafer into the highpressure chamber from the transfer chamber when the valve and the highpressure chamber are both open; closing the valve; closing the highpressure chamber; creating a vacuum in a space between the high pressurechamber and walls of the process chamber; introducing a fluid or gasinto the high pressure chamber and processing the wafer; venting thehigh pressure chamber; opening the high pressure chamber while the valveis closed; pumping the vacuum in said space to equalize pressure betweensaid space and the transfer chamber; opening the gate valve; andremoving the wafer via the transfer chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described with respect to one or more preferredembodiments using a number of figures in which:

FIG. 1 illustrates a prior art cluster tool having an annularconfiguration;

FIG. 2 illustrates a prior art cluster tool having a linearconfiguration;

FIG. 3 illustrates a cluster tool in accordance with the presentinvention having an annular configuration;

FIG. 4 illustrates a cluster tool in accordance with the presentinvention having a linear configuration.

FIG. 5 shows a cross-sectional side view of the process chamber inaccordance with one embodiment of the present invention, with the highpressure chamber open.

FIG. 6 shows a perspective view of one embodiment of the high pressurechamber in accordance with the present invention.

FIG. 7 shows an exploded top perspective view of the major components ofone embodiment of the high pressure chamber.

FIG. 8 shows an exploded bottom perspective view of the components seenin FIG. 7.

FIG. 9 shows a cross-sectional side view of the process chamber of FIG.5, with the high pressure chamber closed FIG. 10 shows an exemplary flowdiagram for using the process chamber.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 3 shows a cluster tool 300 in accordance with the present inventionhaving an annular configuration. The cluster tool 300 has a transferchamber 302, robot 304 with a robot handle 310, conventional vacuumprocess chambers 306B, 306C, 306D, 306E and a load lock 316, all ofwhich are similar to their counterparts in FIG. 1. The cluster tool 300additionally has at least one process chamber 320 configured toselectively form a high pressure chamber 322 in cooperation with avacuum chamber 324, depicted in FIG. 4 as an inner box and a outer box,respectively. The robot 304, robot handle 310, transfer chamber 302 andthe various chambers are configured such that a wafer 308 seated on thearm 310 may be selectively transported into and out of any of thechambers. The process chamber 320 preferably has the same footprint asthe conventional vacuum process chambers 306B-306E, and so occupies nomore floor space than they do.

FIG. 4 shows a cluster tool 400 in accordance with the present inventionhaving a linear configuration. The cluster tool 400 has a lineartransfer chamber 402, robot 404 with a robot arm 410, conventionalvacuum process chambers 406B, 406C, 406D, 406E, 406F and a load lock416, all of which are similar to their counterparts in FIG. 2. Thecluster tool 400 additionally has at least one process chamber 420configured to selectively form a high pressure chamber 422 within avacuum chamber 424, depicted in FIG. 4 as an inner box and a outer box,respectively. The robot 404, robot arm 410, linear transfer chamber 402and the various chambers are configured such that a wafer 408 seated onthe arm 410 may be selectively transported into and out of any of thechambers. The process chamber 420 preferably has the same footprint asthe conventional vacuum process chambers 406B-406F, and so occupies nomore floor space than they do.

It is understood that the construction of the process chambers 320 and420 preferably are identical, and so only process chamber 320 isdescribed in detail.

FIG. 5 shows a cross-section taken parallel to a side of process chamber320 of FIG. 3. The process chamber 320 comprises a housing 502 and ahigh-pressure chamber assembly 520 seated thereon. In FIG. 5, the highpressure chamber assembly 520 is in the disassembled (or, alternatively,“open”, or “non-operative”) position within the process chamber 320. Inthe discussion below, reference numeral 520 is used to denote both thehigh pressure chamber and the high pressure chamber assembly, it beingunderstood that the term ‘high pressure chamber’ refers to the assemblyin the “assembled” (or, alternatively, “closed” or “operative”)position.

The housing 502 comprises a front wall 504, a bottom wall 505 and threeother side walls, shown generally as 506. A substantially rectangularslot 508 is formed in the front wall 504. The slot 508 is of sufficientsize to allow the robot handle 310 to enter and place or remove a wafer308. The slot 508 is operated by a rectangular gate valve 510, sometimesreferred to as a ‘slot valve’ or a ‘transfer valve’. As seen in thefigures, the gate valve 510 includes an upper actuator portion 512 and adrive portion 514. In a preferred embodiment, a Series 2 MONOVATO® gatevalve from VAT Inc. of Woburn, Mass. (www.vatvalve.com) is used.

An adapter 516 connects the process chamber 320 to the cluster tool 300.During use, the purpose of the gate valve 510 is to selectively isolatethe transfer chamber 302 from the process chamber 320 so as toeffectively prevent the flow of gases and other materials from one tothe other.

The high pressure chamber assembly 520 comprises an upper chamberportion 522, a lower chamber portion 524, and a plurality of hydrauliccylinders 526 a, 526 b, 526 c, 526 d connecting the two portions.

The upper chamber portion 522 comprises an upper wall 528 having anoutwardly facing upper surface 530 and an inwardly facing lower surface534. A ring-like upper chamber plate 532 is mounted in a recess 533formed on the inwardly facing lower surface 534. A plurality of inletsand outlets, shown generally as 536, connect to upper through passages538 formed through both the upper wall 528 and the upper chamber plate532. The inlets, outlet and upper through passages permit theintroduction, exit and conveyance of fluids such as gases and liquidsinto and out of portions the high pressure chamber 520. The externalplumbing, tubing, connections, gas and liquid cylinders and the likehave been omitted from the figures, as these are known to those skilledin the art, exemplified by the aforementioned prior art patents.

The lower chamber portion 524 comprises a lower wall 540 having a flatinwardly facing surface 542. The lower chamber portion further comprisesa lower plate 544 having a back surface 546 and an operative frontsurface 547. The lower plate 544 is mounted onto the lower wall 540 withthe back surface 546 of the lower plate 544 abutting the flat inwardlyfacing surface 542 of the lower wall 540.

The lower plate 544 may be provided with a plurality of lower throughpassages 545 for the conveyance of fluids that were introduced via theupper through passages 538 formed in the upper chamber portion 522.Preferably, some of the lower through passages are aligned with theupper through passages 538. Furthermore, the back surface 546 of thelower plate 544 may be provided with a plurality of laterally extendingchannels 548 for collection and further conveyance of fluids backtowards upper through passages from which they may exit the highpressure chamber via the upper surface 530 of the upper chamber portion.

Thus, for the high pressure chamber 520, all mechanical and fluidpenetrations for gases, liquids and other materials and items, are madeonly in one of the two portions. Specifically, they are made in theupper wall 528 of the upper chamber portion 522. The lower chamberportion 524, and especially its lower wall 540, are devoid of throughpassages configured to carry gases, liquids, and the like, to theinterior of the high pressure chamber 520. It should therefore beevident, then, that all external connections for the high pressurechamber 520 only come into the upper chamber portion. This permits thelower chamber portion 524 to be completely isolated from the externalsurfaces of the process chamber 320.

The ring-like upper plate 532 and the lower plate 544 may be providedwith a variety of structures and formations such as wafer supportfingers 560, pockets 562, and the like for supporting and receivingwafers or other workpieces, all as known to those skilled in the art.When the high pressure chamber is in the closed position, the fingers560 are received in the pockets 562. (See FIGS. 5 and 9).

With reference to FIGS. 7 and 8, the ring-like upper plate 532 a and thelower plate 544 a, show additional features. The radially inner edge ofthe upper plate 532 a is provided with a pair of arcuate tracks 535configured and dimensioned to receive correspondingly configured anddimensioned arcuate distribution elements 554, which form a “showerhead”for promoting uniform distribution of a liquid over a wafer.

The operative front surface 547 of lower plate 544 a preferably isprovided with a circular groove 552 configured and dimensioned toreceive a O-ring seal (not shown) that provides the high pressure sealwhen the high pressure chamber is pressurized. The upper operative frontsurface 547 may also be provided with a plurality of narrow pockets 562configured and dimensioned to receive wafer support fingers 560 when thehigh pressure chamber is closed, the fingers 560 themselves beingaffixed to, and suspended from, the inwardly facing lower surface 534.

Furthermore, as best seen in FIG. 8, the back surface 546 of the lowerplate 544 a is provided with a plurality of laterally extending channels548 a associated with pockets 562 formed on the upper operative frontsurface 547. Preferably, at least one laterally extending channel 548 b,not associated with a pocket 562, is also provided on the back surface546.

As best seen in the exploded views of FIG. 7 and 8, the hydrauliccylinders 526 a, 526 b, 526 c, 526 d each comprise a cylinder head 525a, 525 b, 525 c, 525 d, respectively, and a cylinder rod 527 a, 527 b,527 c, 527 d, respectively. The top portions of the cylinder rods areretained in the cylinder head while rods themselves pass throughopenings in the upper chamber portion 522 and the lower chamber portion,and emerge in recesses 570 formed on the underside of the lower wall540. Within these recesses 570, the rods pass through flange-likepressure fittings 572 secured in the recesses by bolts 574, and arethemselves secured by nuts 576.

The high pressure chamber 520 is connected to the process chamberhousing 502 via a peripheral lip 584 formed on the underside of theupper surface 530. As seen in the figures, the lip 584 of the upperchamber wall 528 abuts the top edge of the front wall 504 and side walls516 of the housing 502. The lip 584 is secured to the top edges by bolts(not shown). This forms a seal between the upper chamber wall 528 andthe process chamber housing 502. Furthermore, in this arrangement, thewalls 504, 516 of the housing 502 support the weight of the highpressure chamber 520.

In the arrangement depicted in FIG. 5, the high pressure chamberassembly 520 is disassembled in the sense that the upper chamber portion522 and the lower chamber portion 524 are separated from one another. Insuch case, the pressure throughout the process chamber 320 is uniform.And if the gate valve 510 is open, then the pressure in both thetransfer chamber 302 and the process chamber 320 is the same.

FIG. 9 shows the process chamber 320 of FIG. 5 with the high pressurechamber assembly 520 in the assembled (or, alternatively, “closed”, or“operative”) position. In FIG. 9, the front wall 504 is depicted as asolid wall (i.e., minus the slot 508), and the gate valve 510, theadapter 516 and the transfer chamber 302 have been removed to focus onthe high-pressure chamber 520 (which may also be referred to as the“first”, or “primary” chamber) and a vacuum chamber 590 (which may alsobe referred to as the “second” or “auxiliary” chamber) formed within theprocess chamber 320.

As seen in FIG. 5, when the high pressure chamber is open, there is aspace 578 of a first size between the lower wall 540 of the lowerchamber portion 524 and the bottom wall 505 of the housing. As seen inFIG. 9, when the high pressure chamber is closed, there is a space 579of a second, larger size between the lower wall 540 of the lower chamberportion 524 and the bottom wall 505. This enlarged space 579 is theresult of the upward movement of the lower chamber portion 524 away fromthe bottom wall 505; it is this enlarged space 579 that forms part ofthe vacuum chamber 590.

From the above description, it should be evident that the housing'sfront wall, bottom wall and side walls, and the upper chamber portion522, together define a compartment. This compartment is accessible viathe slot 508, which is selectively sealed by gate valve 510. The lowerchamber portion 524 resides in this compartment as do the spaces 578 and579 when the high pressure assembly is open and closed, respectively.

To adjust the high pressure chamber from the disassembled position tothe assembled position, a hydraulic power unit (not shown) is used toactivate the hydraulic cylinders. This causes the lower chamber portion524 to move in an upward direction, away from the housing bottom wall505 and towards the upper chamber portion. A pressure of between 800 psiand 1,200 psi is applied for this purpose, which results in the lowerchamber portion 524 contacting the upper chamber portion 522 to therebyform the high pressure chamber 520 enclosing a first space in whichprocessing may take place. During wafer processing operations, thehydraulic power unit can be further activated to apply a pressure ofanywhere from 4,000 psi to 10,00 psi, as needed.

With the gate valve 510 closed, and the high pressure chamber 320assembled, a vacuum may be applied via opening 580 formed in the housingside wall to create a vacuum chamber 590 in a space between the lowerchamber portion 524 and the housing bottom wall 505. In such case, theprocessing chamber 320 has both a high pressure chamber 520 and a vacuumchamber 590 coexisting within the process chamber and sharing the lowerchamber portion as a boundary. Specifically, the high pressure chamber520 is formed between the upper chamber portion 522 in abutment with thelower chamber portion 524, and the vacuum chamber is formed in the space579 between the lower chamber portion 522 and a bottom wall 505 of thehousing. Thus, during operation, the transfer chamber 302 and the space579 within the vacuum chamber 590 are typically below atmosphericpressure, while a first space defined within the high pressure chamber520 where the wafer is being processed is well above atmosphericpressure.

A preferred method for using the process chamber 320 with the annularcluster tool 300 is now described with reference to a supercritical CO₂application, and the flow diagram 1000 of FIG. 10.

In step 1010, the robot 304 obtains a wafer 308 which is placed on therobot's handle 310. In a preferred embodiment, the robot 304 would havepicked up the wafer from one of the other vacuum process chambers306B-306E. The transfer chamber 302 during this time is under vacuum, atabout 80-100 mTorr.

In step 1012, the gate valve 510 between the transfer chamber 302 andthe process chamber 320 is then opened. At this point, the high pressurechamber 520 is open; that is, the lower chamber portion 524 is loweredrelative to the upper chamber portion 522. When the gate valve 510 isopened, the entire processing chamber 320 will be under a common vacuum,as will the transfer chamber 302.

In step 1014, the robot 304 will extend its handle 310 and place thewafer 308 on fingers or other structures inside the open high pressurechamber. The robot will then retract into the transfer chamber 302.

In step 1016, the gate valve 510 then closes. This isolates the vacuumpressure in the transfer chamber 302 from that in the process chamber.

In step 1018, the high pressure chamber closes. This results in threeisolated regions—the transfer chamber 302, the closed high pressurechamber 520 in which the wafer is placed, and the vacuum chamber 590formed between the process chamber housing 502 and the closed highpressure chamber 520.

At this point, all three isolated regions are at vacuum. A first vacuumpump is used to create a first vacuum level in the transfer chamber 302while a second vacuum pump is used to create a second vacuum level inthe vacuum chamber 590. Preferably, the second vacuum level is to agreater degree (i.e., to a lower vacuum pressure) than the first vacuumlevel.

Next, in step 1020, high pressure fluid is introduced into the highpressure chamber 520. In a preferred embodiment, the high pressure fluidis CO₂, and the pressure is between 4,000 psi and 10,000 psi. Anyleakage will enter the vacuum chamber 590 around the high pressurechamber 520 and will be pumped before it can affect the transfer chamber302 and the other process chambers 306B-306E.

The wafer 508 is then processed by the high pressure fluid, such as byexposure to the high pressure fluid for a predetermined length of time.

In step 1022, after processing is complete, the fluid in the highpressure chamber 520 is vented to atmosphere. The vent to the highpressure chamber 520 is then closed. At this juncture, there will be aresidual amount of fluid at atmospheric pressure in the high pressurechamber 520.

Then, in step 1024, the high pressure chamber 520 is opened. Because thevacuum chamber 590 is at a vacuum, the residual amount of fluid willflash. At this point, the gate valve 510 is still closed, so theresidual fluid is still isolated from the transfer chamber.

In step 1026, the vacuum chamber 590 (which now also includes the regionbetween the upper chamber portion and the lower chamber portion) is thenpumped until the residual fluid is removed and the pressure is equal onboth sides of the gate valve 510. Failing to equalize the pressure inthe vacuum chamber 590 and the transfer chamber 302 may result inparticles migrating from one to the other due to the pressuredifferential.

Finally, in step 1028, the gate valve 510 is then opened and the wafer508 is removed by the robot 504.

Although the present invention has been described to a certain degree ofparticularity, it should be understood that various alterations andmodifications could be made without departing from the scope of theinvention as hereinafter claimed.

1. A method for cleaning a wafer in a cluster tool, the cluster toolcomprising a transfer chamber and a process chamber connected via afirst valve to the transfer chamber, the process chamber including ahigh pressure chamber comprising an upper chamber portion and a lowerchamber portion movable relative to the upper chamber portion, the highpressure chamber being adjustable between an open position in which thelower chamber portion is spaced apart from the upper chamber portion,and a closed position in which the lower chamber portion contacts theupper chamber portion to thereby enclose a first space, a second spacebeing formed between the lower chamber portion and walls of the processchamber when the high pressure chamber is in the closed position, themethod comprising: introducing the wafer into the high pressure chamberfrom the transfer chamber, when the first valve and the high pressurechamber are both open; closing the first valve to thereby isolatepressure in the transfer chamber from pressure in the process chamber;closing the high pressure chamber to thereby isolate pressure in thefirst space within the high pressure chamber from pressure in the secondspace between the high pressure chamber and walls of the processchamber; introducing a fluid or gas into the high pressure chamber toclean the wafer; venting the high pressure chamber after cleaning thewafer to thereby allow at least some of said fluid or gas to escape, andthen closing the vent; opening the high pressure chamber while the firstvalve is closed; opening the first valve; and removing the wafer via thetransfer chamber.
 2. The method according to claim 1, furthercomprising: pumping the vacuum in the process chamber to equalizepressure between the process chamber and the transfer chamber, afteropening the high pressure chamber and before opening the first valve. 3.The method according to claim 1, further comprising: creating a firstvacuum level in the transfer chamber after closing the first valve; andcreating a second vacuum level in the second space between the highpressure chamber and walls of the process chamber, after closing thehigh pressure chamber.
 4. The method according to claim 3, wherein thesecond vacuum level is at a lower pressure than the first vacuum level.5. The method according to claim 1, wherein: the wafer is introducedinto the high pressure chamber from the transfer chamber under vacuum.6. The method according to claim 1, wherein: closing the high pressurechamber comprises raising the lower chamber portion relative to theupper chamber portion; opening the high pressure chamber compriseslowering the lower chamber portion relative to the upper chamberportion.
 7. The method according to claim 6, comprising: activatinghydraulic cylinders which connect the upper chamber portion to the lowerchamber portion, to raise or lower the lower chamber portion relative tothe upper chamber portion.
 8. A method for cleaning a wafer in a processchamber of a cluster tool having a transfer chamber connected to theprocess chamber, the process chamber including a high pressure chamberadjustable between an open position in which a wafer may be inserted orremoved and a closed position in which said wafer may be cleaned, themethod comprising: introducing the wafer into the high pressure chamberfrom the transfer chamber, when the high pressure chamber is open;closing the high pressure chamber to thereby form a first space in whichsaid wafer is present, and a second place between the closed highpressure chamber and walls of the process chamber; introducing a fluidor gas into the first space of the high pressure chamber for cleaningthe wafer; removing at least some of said fluid or gas from the highpressure chamber; opening the high pressure chamber within the processchamber; equalizing pressure between the process chamber and thetransfer chamber; and removing the wafer via the transfer chamber. 9.The method according to claim 8, further comprising: closing a firstvalve after introducing the wafer into the high pressure chamber fromthe transfer chamber, but before closing the high pressure chamber, thefirst valve being located between the transfer chamber and the processchamber; venting the high pressure chamber with the first valve closed,before opening the high pressure chamber; and opening the first valveafter equalizing pressure between the process chamber and the transferchamber, but before removing the wafer via the transfer chamber.
 10. Themethod according to claim 9, further comprising: creating a first vacuumlevel in the transfer chamber after closing the first valve; andcreating a second vacuum level in the second space, after closing thehigh pressure chamber.
 11. The method according to claim 10, wherein thesecond vacuum level is at a lower pressure than the first vacuum level.12. The method according to claim 8, wherein: the wafer is introducedinto the high pressure chamber from the transfer chamber under vacuum.13. The method according to claim 8, wherein: closing the high pressurechamber comprises raising a lower chamber portion relative to an upperchamber portion; opening the high pressure chamber comprises loweringthe lower chamber portion relative to the upper chamber portion.
 14. Themethod according to claim 13, comprising: activating hydraulic cylinderswhich connect the upper chamber portion to the lower chamber portion, toraise or lower the lower chamber portion relative to the upper chamberportion.
 15. A method for cleaning a wafer in a process chamber that isconnected via a first valve to a transfer chamber of a cluster tool, theprocess chamber including a high pressure chamber adjustable between anopen position in which a wafer may be inserted or removed and a closedposition in which said wafer may be processed, the method comprising:introducing the wafer into the high pressure chamber from the transferchamber when the valve and the high pressure chamber are both open;closing the first valve; closing the high pressure chamber to form afirst space therein; creating a vacuum in a second space between thehigh pressure chamber and walls of the process chamber; introducing afluid or gas into the first space of the high pressure chamber andprocessing the wafer; venting the high pressure chamber; opening thehigh pressure chamber while the first valve is closed; equalizingpressure between the process chamber and the transfer chamber; openingthe first valve; and removing the wafer via the transfer chamber.